Register Now

In order to be able to post messages on the Ford Focus Forum, Ford Focus ST Forum, Ford Focus RS Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:

Password

Please enter a password for your user account. Note that passwords are case-sensitive.

Password:

Confirm Password:

Email Address

Please enter a valid email address for yourself.

Email Address:

Log-in

User Name

Remember Me?

Password

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Not sure on that calculation. C-F-M has a calculator to use when you are looking at their Cometic's head gasket. not sure what all the numbers should be for a stock block and or head. Stock compression is 10.2:1. 0.50 is a large (think most are 20-30 thousandths) but not sure if you would get a full extra number on the left side.

I think at 0.050 you also are making the Zetec an interference type motor. I have asked before but dont recall ever getting an actual hard number of if you remove X material.

I think you will want a tune with that large of a change of compression also.

10.2:1 is the SVT's Compression ratio. The normal zetec's is 9.5:1 wish I could remember the how much to shave but I can't

I've never understood how if the gears are tightened after the belt is set how there would be an issue.

The tensioner should be able to adjust for all but the most drastic milling.

11-15-2012 07:24 PM

79mgb

Quote:

Originally Posted by ah1f39

.040 was the number I was considering for the ported head.

That seems to be the most reasonable amount for higher compression. I could avoid dealing with cam timing and tensioner issues.

11-15-2012 07:14 PM

ah1f39

.040 was the number I was considering for the ported head.

11-15-2012 07:07 PM

79mgb

I realized after I posted that I asked a question that was difficult to answer without knowing all the variables. Thanks for mentioning the calculator. That helped a good bit.

I think .050" will be a little too extreme anyways. Thanks for helping me out. I'm really liking this forum.

11-15-2012 06:44 PM

Magus2727

Not sure on that calculation. C-F-M has a calculator to use when you are looking at their Cometic's head gasket. not sure what all the numbers should be for a stock block and or head. Stock compression is 10.2:1. 0.50 is a large (think most are 20-30 thousandths) but not sure if you would get a full extra number on the left side.

I think at 0.050 you also are making the Zetec an interference type motor. I have asked before but dont recall ever getting an actual hard number of if you remove X material.

I think you will want a tune with that large of a change of compression also.

11-15-2012 10:31 AM

79mgb

After doing a little more research, it looks like 11.15:1. Does that seem right?

11-15-2012 09:56 AM

79mgb

Decked Zetec Head Question

Hey guys. I'm trying to figure out what compression ratio a standard Zetec head decked to .050" would give me. I've tried searching around the forum but the CR's are all over the map.

I'm going to be using a stock block. I don't mind running on premium fuel, I just don't want to be running on racing fuel.

Focus Fanatics Ford Focus Forum offers many fun ways for you to engage with other Ford Focus Owners from across the world. Whether it be about the aftermarket performance modifications, technical how-to's, European tuned suspension or awesome fuel economy similar to the Audi S3, Ford Fusion and Acura TLX. You can find all Ford Focus and Focus ST related information here. Join our Ford Focus discussion forums and chat with local Focus enthusiasts in your area. Challenger Hellcat - Charger Hellcat